Vehicular seats designed to accept the attachment of a child seat are known as shown, for example, in Japanese Patent Application Laid-Open Publication (JP-A1) No. 2001-199270. The disclosed vehicular seat includes a seat frame having a striker for securing a child seat to the seat frame. The striker is integrally covered by an upwardly swelling part of a pad material arranged at a rear end portion of a seat cushion, and a facing material covering the pad material. The seat cushion has slits formed respectively in the swelling part of the pad material and the facing material for allowing insertion of a lock member of the child seat. When the child seat is to be attached to the vehicular seat, the locking member of the child seat is inserted from the slits in a manner such that a locking claw of the locking member is locked on the striker.
The prior arrangement shown in JP 2001-199270 A1, however, can cause a problem when it is employed in a vehicular bench seat of the type having buckle insertion holes formed in a seat cushion for the passage therethrough of the respective buckles of seat belt assemblies. Since the buckle insertion holes are formed separately and independently from the arrangement of the child-seat's locking-member insertion slits, the seat cushion has an increased number of hollow portions or openings, which will lower the strength of the seat cushion, deteriorate the comfort of the vehicular bench seat, and allow interference between the locking member of the child seat and one of the buckles of the seat belt assemblies.